https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100347
--- Comment #15 from Erik Schnetter <schnetter at gmail dot com> --- When I try to rebuild GCC 10.3 or 10.2, they end up having the same problem. Also, when I enable bootstrapping, bootstrapping fails with differences in many files. Given that this used to work on a previous version of the OS, the problem isn't caused by GCC. One thing that e.g. changed is that there is now a newer version of Apple Clang. Thank you for the help and suggestions.
